Refactoring run-tests.php

I was thinking about making some improvements to our venerable test runner, however I wasn't feeling confident about improving the present code base. Instead, I decided to attempt to refactor it. Here's my work in progress: https://github.com/MaxSem/run-tests It requires Composer only for development, and has a script to make a single-file distribution, functionally identical to what we presently have. When it comes to integration with php-src, it could be moved to a subdirectory there or be kept in a separate repository and be used to generate a new run-tests.php whenever needed. Is there interest in this, should I continue? Any suggestions? -- Best regards, Max Semenik